x86: interrupt routing question
From: Mike Galbraith
Date: Tue Jul 12 2011 - 03:47:40 EST
Greetings,
I have an x3550 M3 box which shows different behavior than my Q6600
desktop box. The below is the rt kernel, but it doesn't matter which
kernel I boot, all interrupts are on CPU0 unless I move them. On Q6600
box, IRQs magically appear on every cpu in the affinity mask. Change
the eth0 mask while flood pinging, numbers start/stop changing on the
fly.
On x3550 M3, setting eg IRQ 63's mask to '0xe' will move irq to CPU2,
but nothing that I have found will make the thing behave the same as
trusty old Q6600 box, which seems strange. Is this some kind of BIOS
thingie, or is every kernel busted on this hardware? Busted kernel
seems highly doubtful.
OT question. I have HT turned off on the x3550 because I do rt testing
on it, and occasionally boot idle=poll. Is it still the case that you
should not run idle=poll with HT enabled, or can you do that with HT
these days (E5620 CPU) without munching too many cycles?
CPU0 CPU1 CPU2 CPU3
0: 132 0 0 0 IO-APIC-edge timer
1: 0 0 0 0 IO-APIC-edge i8042
3: 1 0 0 0 IO-APIC-edge
4: 1 0 0 0 IO-APIC-edge
8: 26 0 0 0 IO-APIC-edge rtc0
9: 0 0 0 0 IO-APIC-fasteoi acpi
14: 0 0 0 0 IO-APIC-edge ata_piix
15: 0 0 0 0 IO-APIC-edge ata_piix
16: 5450 0 0 0 IO-APIC-fasteoi megasas
17: 52 0 0 0 IO-APIC-fasteoi ehci_hcd:usb2, uhci_hcd:usb3, uhci_hcd:usb5
18: 0 0 0 0 IO-APIC-fasteoi uhci_hcd:usb4, uhci_hcd:usb6
19: 61939 0 0 0 IO-APIC-fasteoi ehci_hcd:usb1, uhci_hcd:usb7
21: 0 0 0 0 IO-APIC-fasteoi ata_piix
54: 3 0 0 0 PCI-MSI-edge ioat-msix
55: 3 0 0 0 PCI-MSI-edge ioat-msix
56: 3 0 0 0 PCI-MSI-edge ioat-msix
57: 3 0 0 0 PCI-MSI-edge ioat-msix
58: 3 0 0 0 PCI-MSI-edge ioat-msix
59: 3 0 0 0 PCI-MSI-edge ioat-msix
60: 3 0 0 0 PCI-MSI-edge ioat-msix
61: 3 0 0 0 PCI-MSI-edge ioat-msix
62: 178 0 0 0 PCI-MSI-edge eth1-0
63: 6327232 0 0 0 PCI-MSI-edge eth1-1
64: 73 0 0 0 PCI-MSI-edge eth1-2
65: 6327230 0 0 0 PCI-MSI-edge eth1-3
66: 2 0 0 0 PCI-MSI-edge eth1-4
NMI: 0 0 0 0 Non-maskable interrupts
LOC: 2096607 2366453 260343 2225391 Local timer interrupts
SPU: 0 0 0 0 Spurious interrupts
PMI: 0 0 0 0 Performance monitoring interrupts
PND: 0 0 0 0 Performance pending work
RES: 1981 2973 2405 2001 Rescheduling interrupts
CAL: 49 43 74 72 Function call interrupts
TLB: 638 784 1175 674 TLB shootdowns
TRM: 0 0 0 0 Thermal event interrupts
THR: 0 0 0 0 Threshold APIC interrupts
MCE: 0 0 0 0 Machine check exceptions
MCP: 603 603 603 606 Machine check polls
ERR: 0
MIS: 0
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